Young blood could recharge aging bodies

By Matthew Heimer

Boomers, be nice to your millennial coworkers and neighbors: You may want to borrow their blood someday. Three new studies published this week in the journals Science and Nature Medicine show that injections of blood from young mice can help to strengthen the bodies and brains of older mice. And they raise the possibility that, in the distant future, similar treatments could help human beings fight ailments like Alzheimer’s disease, heart disease and muscular deterioration that plague older adults.

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Wanted: Mouse blood donors; the younger, the better.

The studies followed up on past research that had shown that older mice who shared a blood supply with younger mice tended to have healthier, more youthful tissue than other mice the same age. The old-school way of accomplishing such blood-sharing is through “parabiosis,” which involves stitching two live mice together so that their circulatory systems intermingle. (Best not to contemplate that for too long.)

The new studies took a more direct and somewhat less grotesque approach to the blood-and-youth hypothesis. For one of the Science articles, a team from the University of California, San Francisco extracted plasma from the blood of younger rodents and injected it into older mice; those mice did better on learning and memory tests than those who were given blood from other old mice. The team also found evidence that the younger blood helped the older critters form new neural connections and grow new blood vessels in their brains.

So what’s so special about young mouse blood? The findings in the two other papers suggest the secret ingredient may be a protein called GDF11—which is also found in human blood, and whose concentration in the body is believed to decline with age. Researchers from Harvard found that GDF11 appeared to benefit body and mind alike: Injections of the protein improved muscular strength and heart function in older mice, as measured by grip and treadmill tests, and they also spurred the growth of neurons and brain blood vessels.

There’s also something unsettling about the idea of older adults rejuvenating themselves by consuming the blood of younger, healthier people. On the one hand, Americans in general should probably donate blood far more often than they do: Blood banks estimate that only about 5% of eligible donors actually give.

But blood donors tend to assume their donations are going to accident victims or the very ill. The idea of systematically using young people’s plasma to help older beings feel young again, on the other hand, brings to mind vampires, or the organ harvests of Kazuo Ishiguro’s “Never Let Me Go.” And critics of Social Security and Medicare sometimes object that the programs suck (economic) vitality away from younger Americans to care for the elderly—now, they’ll have a new metaphor to work with.

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About Encore

Encore looks at the changing nature of retirement, from new rules and guidelines for financial security to the shifting identities, needs and priorities of people saving for and living in retirement. Our lead blogger is editor Matthew Heimer, and frequent contributors include editor Amy Hoak, writer Catey Hill, and MarketWatch columnists Elizabeth O’Brien, Robert Powell and Andrea Coombes. Encore also features regular commentary from The Wall Street Journal retirement columnists Glenn Ruffenach and Anne Tergesen and the Director of the Center for Retirement Research at Boston College, Alicia H. Munnell.